Over the years, video capture devices such as webcams have become a popular means of communications, and live video communication over the Internet has become common among users around the world. Such programs as Windows Live Messenger® and Skype® allow users to engage in live, face-to-face conversations. The integration of special effects into video streams generated from webcams is a common feature for webcam programs. Programs are available that allow users to enhance webcam sessions by incorporating such special effects as graphics and augmented reality effects.
Augmented reality refers to technology that enhances a view of a physical world environment with virtual computer-generated effects, such as sound or graphics. Specifically, augmented reality adds graphics, sounds, feedback, among other effects to the real world as it exists. In typical implementations, a fiducial marker is used in the field of view of a video system. The fiducial marker serves as a reference point in the field of view on which graphics are superimposed. However, one perceived shortcoming with current systems that utilize fiducial markers is that partial occlusion may occur, for example, due to a user in the field of view obstructing a portion of the fiducial marker, thereby affecting the placement of graphics onto the fiducial marker.